Natural fiber-reinforced polymer matrix composites have been increasingly used in automotive and other fields because of their good mechanical properties, low density, excellent damping properties and biodegradability. The objective of this work is to develop and characterize a high-performance lightweight kenaf fiber composite that is processed using unconventional processing methods, wet laid process followed with compression molding process. Kenaf fiber mats produced by wet laid process are stacked with high-density polyethylene films and compression molded into plates from which testing samples are prepared. The effects of fiber length, fiber content, and area density on the tensile properties are investigated. The composite samples with the best tensile properties are also evaluated in its flexural, compression, impact, and fire resistance performance. The processing–structure–property relations of the developed kenaf fiber high-density polyethylene composite are systematically studied, which can be broadly applied to other natural fiber composites.